Riding the bus with three infants in a stroller is no easy task, especially when you realize you have a flat tire as soon as you step foot on the pavement of 2nd and University. Luckily, I found The Bicycle Repair Shop. Andy happily filled my tire with air, and when it was flat again an hour later, found a replacement tube in minutes. He changed the tire with the babies still in the stroller! This was such an amazing experience that totally made a fun day possible for us! Thank you, Andy!
If you’re going to use the chain whip you just made, you’ll also need a way to get that cassette off. A lockring remover is a must-have; unless you use one of the shady removal methods I’ve seen on the internet—which I wouldn’t necessarily recommend unless you don’t care much about the condition of the wheel after you use them. I recommend Park Tool’s iterations here that cost about $6, but you’ll need to buy the specific one for your brand/type of cassette. (By the way, I’m assuming you already have an adjustable wrench laying around somewhere to use with this tool. If you don’t, well, you’ll need one of those too.)
Basic first aid supplies: A few bandages of varying sizes. 6 Aspirin, or other OTC painkiller of choice. A few alcohol pads in sealed foil packs, useful for cleaning grease off grease and grit off of the bike, and also cleaning cuts on yourself if you take a spill. 1 day supply of any prescription drugs you need to take regularly. Wrap these up in tinfoil and tuck away. It might just save your day.

Keychain style flashlight or headlamp, LED type, not incandescent: The keychain style is tiny and lightweight, the headlamp style is a bit bulkier but easier to use. You can get these for a couple of bucks or less at the local big box hardware store. The LED ones are lighter, more durable and last considerably longer. Very useful if you need to make a repair after dark! I keep a keychain style one as a backup as I normally have a headlamp in my backpack.

A two-stage hand pump tries to marry the best features of both types of pumps: the quick inflation of high volume that can achieve the higher psi ranges of high pressure. But to steal a quote from our floor pump guide, “You pump eight times or you pump 10 times—what does it matter?” That’s a quote from Daimeon Shanks, who at the time was a mechanic for the Garmin-Sharp pro tour team—that’s right, Tour de France, baby.
Modern bottom brackets use a sealed bearing type construction that keeps water and debris locked out, so they seldom go wrong. Maintenance is impossible so they need replacing when they do wear out. Older style cup bottom brackets need to be re-greased every now and again, and occasionally will need to have their bearings replaced. There are a lot more teeth on the chainring cogs than those on the rear cassette, so need changing less regularly. Cranks usually a solid one piece construction so there is not much to go wrong.